Improvement of electrochemical properties of Li1.1Al0.05Mn1.85O4 achieved by an AlF3 coating

The electrochemical performance of AlF3-coated Li1.1Al0.05Mn1.85O4 spinel was investigated. The morphology of the AlF3-coated Li1.1Al0.05Mn1.85O4 was observed by SEM and TEM, and the thickness of the coating layer was approximately 10 nm. Capacity retention and rate capability were substantially improved by the AlF3-coating, as compared to pristine Li1.1Al0.05Mn1.85O4. Manganese dissolution was also dramatically reduced for the AlF3-coated Li1.1Al0.05Mn1.85O4, which may reflect lower impedance for the coated spinel. The thermal stability of the AlF3-coated Li1.1Al0.05Mn1.85O4 was improved, exhibiting an exothermic reaction at higher temperature with reduced heat generation, compared to the pristine Li1.1Al0.05Mn1.85O4.